Originally posted by hogenbor
I can remember a heated thread where people stated that it was physically impossible even for a 262 to break the sound barrier. I am not in a position to comment on that as I don't understand the physics nearly well enough.
The myth that a F-86 broke the sound barrier first (before the X-1) is more credible, but it seems that Bell and Yeager don't want their thunder stolen, even after all these years. But if I'm not mistaken the F-86 was capable of it, in a dive of course.
Planes like the Me 262, Me 163. P-80 and P-84 simply generated too much drag to exceed Mach 1.0. Even in a vertical dive, at full throttle. Aero loads due to drag were sufficient to damage and even destroy these aircraft. The latter two had laminar flow wing designs, which delayed the drag rise a bit, but could not limit it enough.
Welch's forays above Mach 1 were due to the XP-86 being designed as a transonic aircraft. North American knew that with adequate thrust, the design was capable of speeds up to Mach 1.18 in a dive. They informed the USAAF of this early in 1947. When the USAAF officially became the USAF in 9/47, the Secretary of the Air Force notified North American that they were not to push the XP-86 up to transonic speeds until the XS-1 (later renamed X-1) had accomplished its mission of exploring transonic flight. Their primary reason for this was that they did not want to put their experimental budget at risk. Why would Congress authorize big allocations of money when a production prototype could be used for much of the same research? Added to this was the fact at Larry Bell was a close personal friend of Truman. Bell had been informed that the XP-86 should be able to break the "sound barrier" in a slight dive and immediately went to see the President. Truman promised Bell that the Bell XS-1 would get the first shot at supersonic flight, and actually dictated a letter to the Air Force stating that this is what he desired.
USAF documents for the XP-86 program show a chart ordered prepared by Al Boyd for the purpose of keeping the XP-86 at subsonic speeds until the XS-1 had accomplished its purpose for existing. This chart was issued to USAF test pilot Ken Chilstrom, who was to fly the Phase II flight program after the plane was handed over by North American. It was North American that managed and flew the Phase I program, with George Welch at the controls.
One problem for the Air Force was that it had no control over what non-government corporations did. North American agreed to this request in the belief that the XS-1 would be ready for a record run before the XP-86 was completed. However, due to handling issues and an extremely cautious flight schedule, the XS-1 program was creeping along at a snail's pace. Rocket motors were taking longer to develop than expected as well. Any chance that the XS-1 would win the race evaporated when the XS-1 experienced trim problems. Yeager ran out of trim adjustment at Mach .94. This required a major change to the plane that allowed North American to get the XP-86 into the air two weeks before the XS-1 could go for the record.
On its first flight (10/1/47), the XP-86 exceeded Mach 1 when to satisfy his own inner urge, Welch ignored the USAF directive, departed from the flight card and rolled the XP-86 into a dive. It is estimated that the XP-86 attained Mach 1.04 during the dive. Welch repeated this again on October 14th, roughly 60 minutes before Yeager and the XS-1 was released from its B-29 mothership for its first full power run, being the first to exceed Mach 1 in level flight (the XS-1 was actually climbing slightly).
In 2001, the USAF backhandedly acknowledged Welch's flights by officially changing their claim for Yeager and the XS-1 as being the first to exceed Mach 1
IN LEVEL FLIGHT. For the full story of these events, find a copy of Aces Wild, written by retired North American test pilot, Al Blackburn. Released in 1999, published by Scholarly Resources.
You can also read my review blurb on the dust jacket..
My regards,
Widewing
